Harvest can flow axially or tangentially through a threshing unit and/or a separating device for a combine harvester. Different types of devices and combine harvesters can thus differ, depending on the direction of the harvest flow. Tangential combine harvesters and hybrid combine harvesters have a tangential threshing unit. Hybrid combine harvesters have at least one tangential separating device. Axial combine harvesters have, in contrast, an axial separating device, which also has a threshing section. Axial combine harvesters thus do not have a structurally separate threshing unit.
Tangential threshing units include threshing concaves, and axial separating devices include separating concaves. The concaves of the threshing units and the separating devices have passages. These are frequently designed as comb-like finger strips, which are attached to a frame, and form a replaceable concave segment with the finger strips. This has the advantage that when the finger strips are worn out, they can be easily replaced. Furthermore, by changing to finger strips of different sizes, the passages of the separating concave are altered, and adapted to the respective harvest.
In this regard, EP 2 594 126 A1 discloses finger strips of a separating concave which are attached such that they are flush on the frame of a concave segment. The fingers of the finger strips have a free end, which extends freely into space. Furthermore, deflector strips can be attached to the finger strips to improve the separation performance.
The deflector strips can abut the finger strips in a form-fitting manner, merge into them, or extend beyond the finger strips toward the rotor axis.
EP 0 281 383 B2 discloses finger strips of a separating concave, the fingers of which are disposed in an offset manner. The free ends of the fingers of the finger strips likewise extend freely into space. In addition, the finger strips have a T-like structure, wherein an end surface of a leg of the finger strips functions as a deflector surface.
It has been shown that the finger strips of the separating concave, and in particular their fingers ending freely in space, must exhibit a high material strength, in order to withstand the forces and loads acting on them during the separating process. A high material strength leads, however, to a high weight, and to large bending radii.